Manufacture of titanium tetrafluoride



United States Patent MANUFACTURE OF TITANIUM TETRAFLUORIDE Ralph B.Jackson, Dover, Donald H. Keily, Gladstone, and Robert V. Townend,Morris Township. Morris County, N.J., assignors to Allied ChemicalCorporation, a corporation of New York No Drawing. Application February11, 1957 Serial No. 639,225

8 Claims. (Cl. 23-88 This invention relates to processes for manufactureof anhydrous titanium tetrafluoride.

In accordance. with known art, titanium tetrafiuoride, TiF may be madeby reacting metallic titanium or titanium' dioxide with elementalfluorine, or by passing anhydrous HF over titanium tetrafluoride atambient tem peratures or over metallic titanium at red heat. Thesemethods are expensive and uneconomical, and the disadvantages entailedare obvious.

A principal object of this invention lies in provision of processes formaking anhydrous titanium tetrafluoride from the usual commerciallyavailable sources of titanium, i.e. oxygen-containing titanium compoundssuch as ilmenite ores, titanium slags, rutiles and titanium dioxides,and from hydrogen fluoride a common industrial commodity.

Experience shows that it is not possible to make anhydrous TiF, bydirect reaction of HF with titaniferous raw materials containing oxygen.Commercially available sources of titanium all contain oxygenwhichreacts with hydrogen of the HP to form water which may hydrolyze anobjectionable amount of titanium fluoride to titanium oxide compounds.Accordingly, manufacture of anhydrous TiF, by direct one-stepfiuorination of oxidic titaniferous raw materials is not feasible.

In accordance with the present invention, it has been found that thedifllculties arising from inherent water formation and the resultingpotential or actual hydrolysis may be overcome by reacting commerciallyavailable oxidic titaniferous sources of titanium with HF under certainconditions such that the titanium values of the oxidic titanifero-usstarting materials are preliminarily complexed with certain metal ormetals to form metal fluotitanates which, in the preferred practice ofthe invention, are stable hydrated fluotitanates of the metal or metalsemployed for titanium complexing. We find that these hydrated metalfluotitanates may be substantially completely dehydrated by heatingunder certain conditions which eflect elimination of all free andcombined water. In this manner, titanium is maintained in the form ofunhydrolyzable compounds until all water has been removed from thesystem. We also find that, by further heating the dehydrated metalfluotitanate at controlled higher temperatures, it is possible tovolatilize the titanium values of the dehydrated metal fluotitanate andeffect clean separation of titanium, as TiF, vapor, from all othercompounds which may have been employed to initially complex the titaniumvalues of the titaniferous starting material. Hence, practice of theinvention involves conversion of the titanium of oxidic titaniferous rawmaterials to certain metal fluotitanates, in one Way or anothereliminating free and combined water from the system, and thereafterseparating titanium from the dehydrated metal fluotitanate as anhydrousTiF vapor which may be recovered as such or as a white solid on coolingand condensation.

More particularly, in practice of the invention an oxidic titaniferousraw material is reacted with HFin the presence of certain compounds ofcertain metals in such a Way as to tie up substantially all Ti in theform of a dehydratable and subsequently decomposable fluotitanate of themetal or metals used for complexing purposes. The important factors ofthis HF-titaniferous starting, material reaction step are thecomposition of initial oxidic titaniferous raw material, the particularmetal. compounds.- used for complexing purposes, the particular metalsof such compounds, the quantities of such compounds which are presentduring the reaction, quantity and form of. the HF utilized, temperaturesof reaction, and the physical procedures in accordance with which thereaction of theoxidic titaniferous raw material with HF is carried out..

Metal compound which may be used to complex the titanium of the oxidictitaniferous starting material. may" be of the group consisting ofoxides, hydroxides, car-.

bonates and fluorides of aluminum, barium, calcium, iron,

magnesium, and zinc, and any mixtures thereof. Preferred metals arealuminum, calcium, iron, and magnesium. Thus, it will be seen that awide variety of metal compounds, taken singly or in admixture with oneor more other metal compounds, may be utilized in practice of theinvention, and the expression metal com.- pound, unless otherwisemodified, as used herein em,- braces the above designated metal compoundgrouping.-

The term metal herein does not include silicon which? is considered as ametalloid or a non-metal. It will be understood that any one or all ofthe metals named will complex with titanium to form metal fluotitanatessuitable for practice of the invention. To illustrate, assum.-

ing use of e.g. off-grade TiO as starting material, iron oxide alone orsay a mixture of iron oxide, aluminum oxide and calcium oxide may beemployed to complex,

the titanium. In the case of use of the iron oxide alone,

the fluotitanate is iron fluotitanate, and in the case ofthe mixture,the resulting complex is a mixture of iron, aluminum and calciumfluotitanates. In expressions herein such as total metal fluotitanate,the total metal is used to designate either a single metal or the totalof any two or more of the metals above named.

In practice of all embodiments, the amount of titanium complexingcompound employed in the reaction of oxidic titaniferous materialreaction with HP is such as to provide the presence of total metal ofcomplexing metal compound in quantity suflicient to combine withsubstantially all of the formable TiF to produce total-metalfluotitanate. From a more particular viewpoint, the quan-' tity ofcomplexing metal compound employed is such as to provide in the reactionthe presence of total metal of metal compound in amount sufficient tocombine with at least 0.45, and in the best forms of the invention,preferably not less than half as much fluorine as is theoreticallyneeded to react with all titanium present to form TiF Provision in thereaction mass of the fore going amounts of total metal in conjunctionwith the hereinafter noted quantities of HF efiects complexing of thetitanium with total metal of the complexing metal compound to formtotal-metal fluotitanate.

Whether or not metal compound for titanium coinplexing purposes isactually added from extraneous sources to the oxidic titaniferousstarting material de pends upon the composition of the latter. Naturalilmenite ores usually contain a high proportion of metal (other than Ti)compounds which may be utilized to. complex the titanium. Typicalilmenites may analyze Ti as 'IiO 53-60%; total Fe as Fe O 35-38%; Si asSi0 1.04.0%; plus smaller quantities of miscellaneous and P 0 usually asoxides.

. 3 v is iron oxide which may be utilized as a suitable metal compoundfor complexing the titanium. From the foregoing typical analyses, itwill be observed that such ilmenites inherently contain total metal (Fe)of complexing metal compound (iron oxide) in amount more than suflicientto combine with about half as much fluorine as is theoretically needed.to react with sub:tantially all the titanium present to form TiFAccordingly, it will be understood that when utilizing in practice ofthe invention oxidic titaniferous raw materials, such as mosti'lmenites, which inherently contain sufficient complexing metalcompound to provide in the reaction mass total metal of'complexing metalcompound in amount sufi'icient to combine with at least 0.45 andpreferably not less than half as much fluorine as is theoreticallyneeded to react with all titanium present to form T iF it is unnecessaryto add to the oxidic titaniferous starting material or to the reactionany additional complexing metal compound from extraneous sources, ie.

in the case of most ilmenites these materials may be used astitaniferous starting materials on an as is composition basis.

Titanium slags are well known in the art, illustrative methods formaking the same being disclosed in U.S.P. 2,476,453 of July 19, 1949,and U.S.P. 2.631.941 of March 17, 1953. Representative slags may analyze-Ti as TiO and Ti O 65-75%; Fe as FeO 610%; Al as A1 4-5%, Ca as CaO03-17%; Mg as MgO 35%, Si as SiO 4-5 plus small amounts of oxides ofmiscellaneous metals such as Cr, V, Mn and some metallic iron. It willbe noted that in titanium slags, metal compounds which may be used fortitanium complexing purposes are dominantly oxides of iron, aluminum,calcium, and magnesium. Also, it will be understood that in most slagsthe total metal (e.g. Fe plus Al plus Ca plus Mg) of the availabletitanium complexing metal compounds is inherently present in amountinsufficient to combine with at least 0.45 as much fluorine as is neededto react with titanium present to form TiF and facilitate formation oftotal-metal fiuotitanate. Hence, where the oxidic titaniferous rawmaterial employed is such that it does not of itself contain total-metalof total complexing metal compounds in sufficient amount, an additionalquantity of complexing metal compound of the type herein defined isintroduced into the raw material or into the reaction in amountsufiicient to bring available total metal of complexing metal compoundup to the above indicated values. p

' Rutiles usually contain upward of 90% Ti as TiO and hence inherentlycontain very little and wholly insuflicient amounts of complexing metalcompound. while titanium sources such as impure or off-grade TiO containno significant quantities of complexing metal compound. In theseinstances, the complexing metal compound deficiencies are made up,similarly as in the case of titanium slags, by incorporation of thenecessary additional quantities of whatever complexing metal compound isto be employed. Regardless of the composition of the'oxidic titaniferousstarting material, it will be noted that in practice of all embodimentsof the invention the reaction of starting material with HF is carriedout in the presence of total metal of complexing metal compound inamount sufficient to combine with substantially all of the formable TiFto produce total-metal fluotitanates, and to obtain best recoveries,reaction is carried out in the presence of total metal complexing metalcompound in amount sufficient to combinewith at least 0.45 andpreferably not less than half as much fluorine as is needed to reactwith all titanium present to form Til- T he quantity of HF employed inthe complexing reaction is in amount suflicient to convert any siliconcom-- pounds present to SiF all titanium present to TiF and to convertall metal compound, other than. any mjc al fluoride which may bepresent, to metal fluoride. It will be understood that any siliconcompound in the incoming titaniferous material is eliminated from thesystem as SiF during the reaction. As hereafter more particularly noted,metal fluorides are suitable complexing compounds, and hence, when metalfluorides are utilized as complexing agents, the quantity of HF sup-.plied to the reaction may be correspondingly reduced.

Hydrogen fluoride may be employed in the form of anhydrous liquid orgas, or as an aqueous solution having an HF strength preferably not lessthan about 50%. The foregoing preferred minimum of HF concentration, inconjunction with hereinafter noted procedural features, is a factorcontributing to prevention of hydrolysis of titanium compound during thereaction. As a further precautionary measure with regard to preventionof hydrolysis, and also to effect substantially complete formation oftotal-metal fluotitanates, it is preferred to operate with an excess ofHF preferably not less than 10% over theoretical requirements.

The reaction of oxidic titaniferous starting material with HF may becarried out in any suitable externally.

heated reactor at atmospheric pressure or under superatmosphericpressure if so desired. The titaniferous material is usually relativelyfinely divided and may pass 200 mesh. To obtain good HF utilization, itis preferred to employ hydrogen fluoride in liquid anhydrous form, or asaqueous hydrofluoric acid of strength above about 50%, and usually about60% HF strength. Agitation facilitates reaction. Where gaseous anhydrousHF is employed, HF gas may be contacted with the titaniferous materialmaintained in the form of agitated or relatively static beds, and theapparatus may be designed to facilitate feed of gaseous HF at rates suchas to effect good HF utilization.

Reaction of HF with titaniferous raw material takes place at anyreasonably elevated temperature, reaction being significant attemperatures upwards of e.g. 50 C. Particularly when using HP in liquidform and substantially atmospheric pressure, temperatures are preferablynot higher than about 200 C., and more usually temperatures lie in therange of about -150 C.

Any complexing metal compound supplied from extraneous sources may bemixed initially with the incoming titaniferous material, or may beintroduced during the course of the reaction particularly where thelatter is carried out using HP in liquid form. Time of reaction iswidely variable depending upon the particular operation at. hand, but inany case is sufficient to convert the titaniferous starting material tototal-metal fluotitanate. Preferably, especially. when using HF inliquid form, reaction or digestion may be continued until the materialin the reactor is a relatively dry, hydrated total-metal fiuotitanate,i.e. contains no significant amount of free water. We find that when HFis used in the above mentioned concentrations, and reaction procedure issuch that the hydrated total-metal fluotitanate in the reactor isreduced to substantial dryness (substantial absence of free water),possibilities of titanium hydrolysis are minimized.

As indicated, it is preferred to carry out the invention processstepwise, i.e. formation of a hydrated totalmetal fluotitanate, followedby dehydration (removal of combined water), and subsequent decompositionof the dehydrated total-metal fluotitanate. While not preferred,reaction of HF and incoming titaniferous material with formation ofhydrated total-metal fluotitanate and de-.

hydration ofthe same may be carried out in a more or less singlecontinuing step, e.g. at approximate termination of the reaction oftitaniferous material with HF, temperature may be raised sufficiently todehydrate the fluotitanate thus formed. In such circumstance, maximumtemperature may be high enough but not substantially higher than thatneeded to substantially dehydrate total-metal fluotitanate, in whichinstance maximum temperatureshould not exceed about 450 'C. atsubstantially atmospheric pressure. operating convenience, suchprocedure is not preferred.

In usual practice, the reaction of oxidic titaniferous material with HFproceeds at temperatures generally below about 150 C. to the point ofsubstantial dryness of the mass in the reactor. The resulting hydratedtotalmetal fluotitanate may be dehydrated in the reactor or in separatesuitable equipment. In accordance with the invention, dehydration iseflected by heating the reacted mass to within the range of about350-450 C. Purpose of this step is to eliminate all combined water fromthe system with substantially no decomposition of the fluotitanate. Agood average temperature is about 400 C. However, on the other hand,somewhat lower or somewhat higher temperatures may be employed dependingupon the particular nature of the fluotitanate at hand. For any givenconditions of operation, one or two test runs will indicate optimummaximum temperature of dehydration. To insure high ultimate yields ofTiF lower temperatures and longer dehydrating time intervals arepreferred. End point of dehydration may be determined by cessation ofweight loss of the material being dehydrated.

In accordance with the invention it has been found that the titaniumconstituent of the particular total-metal fluotitanates described may beseparated from all other fluotitanate constituents as vaporous TiF byheating the dehydrated total-metal fluotitanates at temperaturesubstantially in the range of 625-750 C. at atmospheric pressure. Forthis purpose, the dehydrated fluotitanates may be charged into asuitable externally heated sublimer equipped with means for, taking offvaporous TiF Heating is continued until exit of TiF from the sublimersubstantially ceases. TiF4 vapors discharged from the sublimer may becooled to recover anhydrous TiF as a White solid. The solid residue inthe sublimer is a mixture of fluorides of the metals of the metalcompounds utilized in the reaction step for titanium complexing. Thus,in the case of utilization of a titanium slag-as raw material, the solidresidue in the sublimer may be a mixture of iron, aluminum, calcium, andmagnesium fluorides plus some unreacted raw material. When utilizingoxidic titanifero-us starting materials which require addition ofcomplexing metal compound from ex traneous sources, We find that thesublimer residue is particularly adaptable for use for this purpose.Experience shows the fluorides of the complexing metals react readilyWith the incoming raw material to form fluotitanates, a mayor advantagebeing that when utilizing metal fluorides as complexing metals overallconsump tion of HF is materially reduced.

Temperatures mentioned herein are taken at substantially atmosphericpressure. Approximately cor-' responding temperatures at suborsuperatmospheric pressures may be employed. For example, at absolutepressure of about 1 mm. of Hg, dehydration temperature may be as low as300 C., and TiF, sublimation temperature may be as low as about 500 C.

In the following examples, unless otherwise. noted, parts andpercentages are by'weight, and the term metal does not include siliconwhich is considered herein as a non-metal.

Example 1.--Ten' parts of about 200 mesh ground ilmenite ore, analyzingtotal titanium as TiO 58.3 total iron as Fe O 35%, and 1.5% Si plusother oxides of metals such as Al, Ca, Mn, Mg, V, and Cr amounting to alittle more than 5% of the ore, were added to about 15.9 parts ofaqueous hydrofluoric acid of- 60% HF strength. The amount of HF employedwas about in excess of that theoretically required to convert all Ti toTiF silica to SiF and all metals other than Ti to metal fluorides. Inthis particular ilmenite, the total metals (other than Ti) inherentlypresent were suflicient to combine with about 0.54 as much fluorine asFrom standpoint of 6 was required to react with all Ti present toproduce TiF that is, the total metals (other than Ti) were inherentlypresent in amount at least sufficient to combine with all TiF to formtotal-metal fluotitanate. Hence, no addition of extraneously introducedtitanium complexing metal compound was necessary. The foregoing mixturewas digested with agitation at about 100 C. SiF and water vapor passedoff, and digestion was continued to approximate dryness. Drying (removalof free water) was completed by heating for several hours at about 110C. The resulting hydrated total-metal fluotitanate cake, mostly ironfluotitanate, was broken up and crushed to pass 100 mesh, The finelydivided material was heated for about one hour at temperature of about400 C. at atmospheric pressure to drive oif all combined water. Oncompletion of dehydration, the material showed a weight loss of about5.9%, an amount corresponding approximately to 2H O hydration of theundehydrated fluotitanate. The dehydrated fluotitanate was heated atabout 700 C. at atmospheric pressure for approximately one hour. TiFsublimed off by decomposition of the fluotitanate complex, was condensedand recovered, and weight loss of the metal fluoride residue in thesublimer was about 62% (dry basis), showing a recovery of TiF of about96% of theory.

Example 2.-In this run, the oxidic titaniferous raw material employedwas approximately 100 mesh titanium slag analyzing total Ti as TiO71.8%, total iron as FeO 6.6%, A1 as A1 0 9.4%, Si as SiO 7.7%, plussmall amounts of oxides of other metals such as calcium,magnesium,-vanadium, chromium and manganese. Twenty parts of the slagwere added in small increments while agitating to about 39 parts ofaqueous hydrofluoric acid of 60% HF strength. The mixture was digestedwith agitation for about an hour at about C. at atmospheric pressure.About 2.4 parts of Ca(OH) in the form of 325 mesh powder were added, andthe resulting mass was further digested at temperature of about C. SiFand water vapor passed off, and digestion was continued to approximatedryness. Drying (removal of free water) was completed by heating forseveral hours at about C., and the resulting hydrated total-metalfluotitanate cake,, mostly iron, aluminum and calcium fluotitanates, wasbroken up and crushed to pass 100 mesh. In the particular titanium slagemployed, the total metals (other than Ti) inherently present weresuflicient to combine with about 0.3 as much fluorine as was required toreact with all Ti present to produce TiF that is, the total metals(other than Ti) inherently in the slag Were present in amountinsufiicient to combine with all TiF to form total-metal fluotitanate.By addition of the Ca(OH) the total metals (otherthan Ti) content of thereaction mass was brought up to a value sufficient to combine with about0.46 as much fluorine as is required to react with all Ti present toproduce TiF that is, after addition of the calcium of the Ca(OH) thetotal metals (other than Ti) were present in amount sufiicient tocombine with mostly all Tilto form total-metal fluotitanate. The amountof HF employed in the digestion operation was about 10% in excess ofthat theoretically required to convert all Ti t0 TiF silica to SiF andall other metals other than Ti to metal fluoride. The above-describedfinely divided total-metal fluotitanate material was heated for aboutone hour at temperature of about 400 C. at atmospheric weight loss ofthe solid metal fluoride residue in the '7 sublimer was about-50.8% (drybasis), showing a TiF recovery of about 82.5% of theory.

Example 3.In this run, the oxidic titaniferous raw material employed wasthe same as the titanium slag of Example 2. Ten parts of the slag wereadded in small increments while agitating to about 17.4 parts of aqueoushydrofluoric acid of 60% HF strength. The mixture was digested withagitation for about an hour at about 80 C. at atmospheric pressure.About parts of the solid metal fluoride sublimate residue of Example 2were added. The residue comprises approximately, about 24% TiF 19% FeF15% AlF 12% MgF and 28% CaF and the resulting mass was further digestedat temperature of about 100 C. SiF and water vapor passed oif, anddigestion was continued to approximate dryness. Drying (removal of freewater) was completed by heating for several hours at about 110 C., andthe resulting hydrated total-metal fluotitanate cake, mostly iron,aluminum and calcium fluotitanate was broken up and crushed to pass 100mesh. As indicated in Example 2, the total metals (other than Ti)inherently present in the initial slag were suflicient to combine withabout 0.3 as much fluorine as was required to react with all Ti presentto produce TiF i.e. the total metals (other than Ti) inherently in theslag were present in amount insuflicient to combine with all TiF to formtotal-metal fluotitanate. By addition of the 5 parts of solid metalfluoride sublimate residue of Example 2, the total metals (other thanTi) content of the reaction mass was brought up to a value sufficient tocombine with about 0.46 as much fluorine as was required to react withall Ti present to produce TiF that is, after addition of the metalfluoride residue, the total metals (other than Ti) were present inamount suflicient to combine with mostly all TiF to form total-metalfluotitanate. The amount of HF employed in the digestion operation wasabout in excess of that theoretically required to convert all Ti to TiFsilica to SiF and all other metals (other than Ti) of the incoming slagincrement to metal fluoride. The above-described finely dividedtotal-metal fluotitanate material was heated for about one hour attemperature of about 400 C. at atmospheric pressure to drive off allcombined water. On completion of dehydration, the material showed aweight loss of about 11.2%, an amount corresponding approximately to 4HO hydration of the undehydrated fluotitanate. The dehydrated complexfluotitanate was heated at temperature of about 700 C. at atmosphericpressure for about an hour. TiF sublimed oil by decomposition of thefluotitanate complex, was condensed and recovered, and weight loss ofthe solid fluoride residue in the sublimer was about 43.8% (dry basis)showing a TiF recovery of about 77.3% of theory on the basis of thetitanium slag charged.

We claim:

1. The process for making anhydrous titanium tetra fluoride whichcomprises reacting at moderately elevated temperature, above about 50 C.and below temperature at which substantial dehydration of hereafterdefined total-metal fluotitanate is effected, oxidic titaniferousmaterial with HF and metal compound of the group consisting of oxides,hydroxides, carbonates and fluorides of aluminum, barium, calcium, iron,magnesium and zinc and mixtures thereof, while providing the presence ofHF in the form of the group consisting of anhydrous HF and aqueoussolution of HF strength not less than about 50%, and in amountsuflicient to convert any silicon compound present to SiF all titaniumpresent to TiF and to convert all metal compound other than metalfluoride present to metal fluoride, and while providing the presence oftotal metal of metal compound in amount sufficient to combine withsubstantially all TiF to form total-metal fluotitanate, heatingresultant reaction materials, to temperature higher than said reactiontemperature and high enough but not substantially higher than thatneeded .to substantially completely dehydrate totalmetal fluotitanate,for a period of time suflicient to drive off substantially all free 'andcombined water to thereby form solid substantially 'completelydehydratedtotal-metal fluotitanate, separating said fluotitanate from evolvedwater; thereafter heatingthe' dehydrated total-metal fluotitanate tohigher temperature above about 500 C. and high enough to decompose thesame to vaporous anhydrous TiF and solid total-metal fluoride residue,and recovering said anhydrous TiF4.

2. The process for making anhydrous titanium tetrafluoride whichcomprises reacting, at moderately elevated temperature above about 50 C.and not substantially higher than 200 C., oxidic titaniferous materialwith HF and metal compound of the group consisting of oxides,hydroxides, carbonates and fluorides of aluminurn, barium, calcium,iron, magnesium and zinc and mixtures thereof, while providing thepresence of HP in the form of the group consisting of anhydrous HFandaqueous solution of HF strength not less than about 50%} and inamount sufficient to convert any silicon compound present to sin, alltitanium present to TiF, and to convert all metal compound other thanmetal fluoride present to metal fluoride, and while providing thepresence of total metal of metal compound in amount suflicient tocombine with substantialy all TiF, to form total-metal fluotitanate,maintaining reaction conditions for a period suflicient to convertsubstantially all metal present to hydrated total-metal fluotitanate,then substantially completely dehydrating said total-metalfluotitanateby heating to temperature higher than said reaction temperature and highenough but not substantially higher than that needed to substantially'completey dehydrate total-metal fluoti-j tanate, thereafter decomposingsaid dehydrated total-metal fluotitanate, by heating at highertemperature above about 500 C., to vaporous anhydrous TiF and solidtotalmetal fluoride residue, 'and recovering said anhydrous TiF 3. Theprocess for making anhydrous titanium tetra fluoride which comprisesreacting, at moderately elevated temperature above about 50 C. and notsubstantially higher than 200 C., oxidic titaniferous material with HFand metal compound of the group consisting of oxides, hydroxides,carbonates and fluorides of aluminum, barium, calcium, iron, magnesiumand zinc and mixtures thereof, while providing the presence of HF in theform of the group consisting of anhydrous HF and aqueous solution of HFstrength not less than about 50%, and in amount sufficient to convertany silicon compound present to SiF all titanium present to TiF -and toconvert all metal compound other than metal fluoride present to metalfluoride, and while providing the presence of total metal of metalcompound in amount suflicient to.

combine with substantially all HR; to form total-metal fluotitanate,heating resultant reaction materials to tem-' perature substantially inthe range of 350-450 C. for a period of time sufiicient to substantiallycompletely dehydrate total-metal fluotitanate, thereafter heating thedehydrated total-metal fluotitanate to temperature above about 625 C. todecompose the same to vaporous anhydrous TiF, and solid total-metalfluoride residue, and recovering said anhydrous TiF 4. The process formaking anhydrous titanium tetrafluoride which comprises reacting atmoderately elevated temperature above about 50 C. oxidic titaniferousmaterial with HF and metal compound of the group consisting of oxides,hydroxides, carbonates and fluorides of alumlnum, barium, calcium, iron,magnesium and zinc and mixtures thereof, while providing the presence ofHF in'the form of the group consisting of anhydrous HF and aqueoussolution of HF strength not less than about 50%, and in amountsuflicient to convert any sill-- con compound present to SiF alltitanium present to TiF and to convertall metal compound other than.metal fluoride present to metal fluoride, and while providing thepresence of total metal of metal compound in amount suflicient tocombine with at least 0.45 as much fluorine as is needed to react withall titanium present to form TiF to thereby produce total-metalfiuotitanate, heating resultant reaction materials, to temerature higherthan said reaction temperature and high enough but not substantiallyhigher than that needed to substantially completely dehydratetotal-metal fluotitanate, for a period of time sufiicient to drive offsubstantially all free and combined water to thereby form solidsubstantially completely dehydrated total-metal fluotitanate, separatingsaid fluotitanate from evolved Water; thereafter heating the dehydratedtotal-metal fluotitanate to higher temperature above about 500 C. andhigh enough to decompose the same to vaporous anhydrous TiF and solidtotal-metal fluoride residue, and recovering said anhydrous TiF 5. Theprocess of claim 1 in which the oxidic titam'ferous material containsless total metal of said metal compound than is needed to combine withall titanium present as T iF to form total-metal fluotitanate, andextraneous metal compound is introduced in quantity to provide in thereaction mass the presence of total metal of metal compound in amountsufiicient to combine with substantially all HR; to form total-metalfluotitanate.

6. The process of claim 1 in which the oxidic titaniferous material istitanium slag containing less total metal of said metal compound than isneeded to combine with all titanium present as TiF to form total-metalfluotitanate, and extraneous metal compound is introduced in quantity toprovide in the reaction mass the presence of total metal of metalcompound in amount suflicient to combine with substantially all TiF toform total-metal fluotitanate.

7. The process of claim 1 in which the oxidic titaniferous materialcontains less total metal of said metal compound than is needed tocombine with all titanium present as TiF to form total-metalfluotitanate, and extraneous metal compound is introduced in quantity toprovide in the reaction mass the presence of total metal of metalcompound in amount sufficient to combine with substantially all TiF toform. total-metal fluotitanate, the foregoing said extraneous metalcompound being the solid total-metal fluoride residue of thedecomposition step of a previous operation.

8. The process of claim 3 in which the oxidic titaniferous material istitanium slag containing less total metal of said metal compound than isneeded to combine with all titanium present as HR; to form total-metalfluotitanate, and extraneous metal compound is introduced in quantity toprovide in the reaction mass the presence of total metal of metalcompound in amount suificient to combine with substantially all TiF toform total-metal fiuotitanate, the foregoing extraneous metal compoundbeing the solid total-metal fluoride residue of the decomposition stepof a previous operation.

References Cited in the file of this patent UNITED STATES PATENTS1,995,334 Svendsen Mar. 26, 1935 2,568,341 Kawecki et a1 Sept. 18, 19512,724,635 Wainer Nov. 22, 1955 OTHER REFERENCES Barksdale: Titanium,1949, page 83.

Mellor: A Comprehensive Treatise on Inorganic and Theoretical Chemistry,Longmans, Green and Co., N.Y., 1927, vol. 7, page 67.

1. THE PROCESS FOR MAKING ANHYDROUS TITANIUM TETRAFLUORIDE WHICHCOMPRISES REACTING AT MODERATELY ELEVATED TEMPERATURE, ABOVE ABOUT 50*C. AND BELOW TEMPERATURE AT WHICH SUBSTANTIAL DEHYDRATION OF HEREAFTERDEFINED TOTAL-METAL FLUOTITANATE IS EFFECTED, OXIDIC TITANIFEROUSMATERIAL WITH HF AND METAL COMPOUND OF THE GROUP CONSISTING OF OXIDES,HYDROXIDES, CARBONATES AND FLUORIDES OF ALUMINYM, BARIUM, CALCIUM, IRON,MAGNESIUM AND ZINC AND MIXTURES THEREOF, WHILE PROVIDING THE PRESENCE OFHF IN THE FORM OF THE GROUP CONSISTING ANHYDROUS HF AND AQUEOUS SOLUTIONOF HF STRENGTH NOT LESS THAN ABOUT 50%, AND IN AMOUNT SUFFICIENT TOCONVERT ANY SILICON COMPOUND PRESENT TO SIF4, ALL TITANIUM PRESENT TOTIF4 AND TO CONVERT ALL METAL COPOUND OTHER THAN METAL FLUORIDE PRESENTTO METAL FLUORIDE, AND WHILE PROVIDING THE PRESENCE OF TOTAL METAL OFMETAL COMPOUND IN AMOUNT SUFFICIENT TO COMBINE WITH SUBSTANTIALLY ALLTIF4 TO FORM TOTAL-METAL FLUOTITANATE, HEATING RESULTANT REACTIONMATERIALS, TO TEMPERATURE HIGHER THAN SAID REACTION TEMPERATURE AND HIGHENOUGH BUT NOT SUBSTANTIALLY HIGHER THAN THAT NEEDED TO SUBSTANTIALLYCOMPLETELY DEHYDRATE TOTALMETAL FLUOTITANATE, FOR A PERIOD OF TIMESUFFICIENT TO DRIVE OF SUBSTANTIALLY ALL FREE AND COMBINED WATER TOTHEREBY FORM SOLID SUBSTANTIALLY COMPLETELY DEHYDRATED TOTAL-METALFLUOTITANATE, SEPARATING SAID FLUOTITANATE FROM EVOLVED WATER;THEREAFTER HEATING THE DEHYDRATED TOTAL-METAL FLUOTITANATE TO HIGHERTEMPERATURE ABOVE ABOUT500* C. AND HIGH ENOUGH TO DECOMPOSE THE SAME TOVAPOROUS ANHYDROUS TIF4 AND SOLID TOTAL-METAL FLUORIDE RESIDUE, ANDRECOVERING SAID ANHYDROUS TIF4.